Across
- 4. protective membrane that surrounds the embryo
- 6. an organism that lives in or on another organism, harming it
- 7. has a backbone
- 10. cannot be cut into equal halves
- 14. shedding and replacing of an exoskeleton, skin, or feathers
- 15. skeleton is on the outside of the body
Down
- 1. symmetry: body parts are arranged in a circle around a center point
- 2. does not have a backbone
- 3. skeleton is on the inside of the body
- 5. symmetry: can be split into left and right sides in only one way
- 8. changes in form as animal becomes an adult
- 9. animal that heats its body from its environment
- 11. animal that generates its body heat from the inside
- 12. organs that exchange carbon dioxide for oxygen in water
- 13. connects fetus to mother for nutrient and gas exchange